/*
 * Downloads all images from your Instagram timeline
 * to your disk and reinserts geo and time EXIF metadata.
 */

// conductance deps
var http = require('sjs:http');
var fs = require('sjs:nodejs/fs');
var string = require('sjs:string');

// node deps
var nodeFs = require('fs');
var nodeHttp = require('https');
var ex = require('exiv2');
var util = require('util');

// read instagram access token from a file called token
// go get a token at https://apigee.com/console/instagram
var accessToken = fs.readFile('token').toString();
var base = 'https://api.instagram.com/v1/users/self/media/recent/?access_token=' + accessToken;
var data = [];
var urlCursor = base;

function downloadItem(item) {
  var file = downloadFile(
    item.images.standard_resolution.url,
    'timeline/' + item.id + '.jpg');

  var timestamp = customFormat(
    new Date(parseInt(item.created_time)*1000),
    '#YYYY#:#MM#:#DD# #hh#:#mm#:#ss#');

  var tags = {
    'Exif.Image.DateTime': timestamp,
    'Exif.Image.DateTimeOriginal': timestamp,
    'Exif.Image.ImageDescription': item.caption ? item.caption.text : ''
  };

  if (item.location) {
    var lat = ConvertDDToDMS(item.location.latitude, false);
    var lng = ConvertDDToDMS(item.location.longitude, true);
    tags['Exif.GPSInfo.GPSLatitude'] = GPSString(lat);
    tags['Exif.GPSInfo.GPSLatitudeRef'] = lat.dir;
    tags['Exif.GPSInfo.GPSLongitude'] = GPSString(lng);
    tags['Exif.GPSInfo.GPSLongitudeRef'] = lng.dir;
  }
  setImageTags(file, tags);
}

while (urlCursor) {
  var response = http.json(urlCursor);
  timeline = timeline.concat(response.data);
  response.data.forEach(downloadItem);
  urlCursor = response.pagination.next_url;
}

fs.writeFile('timeline.json', JSON.stringify(timeline));


/*********** Code found on the internet ***********/

function GPSString(obj) {
  return dec2frac(obj.deg) + ' ' + dec2frac(obj.min) + ' ' + dec2frac(obj.sec);
}

function ConvertDDToDMS(D, lng){
  return {
    dir : D<0?lng?'W':'S':lng?'E':'N',
    deg : 0|(D<0?D=-D:D),
    min : 0|D%1*60,
    sec :(0|D*60%1*6000)/100
  };
}

function downloadFile(path, file) {
  waitfor() {
    var f = nodeFs.createWriteStream(file);
    nodeHttp.get(path,function(res){
        res.on('data', function (chunk) {
            f.write(chunk);
        });
        res.on('end',function(){
            f.end();
            hold(10);
            resume();
        });
    });
  }
  return file;
}


function getImageTags(path) {
  var rv;
  waitfor() {
    ex.getImageTags(path, function(err, tags) {
      rv = tags;
      resume();
    });
  }
  return rv;
}

function setImageTags(path, tags) {
  waitfor() {
    ex.setImageTags(path, tags, function(err){
      resume();
    });
  }
}

function customFormat(date, formatString){
  var YYYY,YY,MMMM,MMM,MM,M,DDDD,DDD,DD,D,hhhh,hhh,hh,h,mm,m,ss,s,ampm,AMPM,dMod,th;
  YY = ((YYYY=date.getFullYear())+"").slice(-2);
  MM = (M=date.getMonth()+1)<10?('0'+M):M;
  MMM = (MMMM=["January","February","March","April","May","June","July","August","September","October","November","December"][M-1]).substring(0,3);
  DD = (D=date.getDate())<10?('0'+D):D;
  DDD = (DDDD=["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"][date.getDay()]).substring(0,3);
  th=(D>=10&&D<=20)?'th':((dMod=D%10)==1)?'st':(dMod==2)?'nd':(dMod==3)?'rd':'th';
  formatString = formatString.replace("#YYYY#",YYYY).replace("#YY#",YY).replace("#MMMM#",MMMM).replace("#MMM#",MMM).replace("#MM#",MM).replace("#M#",M).replace("#DDDD#",DDDD).replace("#DDD#",DDD).replace("#DD#",DD).replace("#D#",D).replace("#th#",th);
  h=(hhh=date.getHours());
  if (h===0) h=24;
  if (h>12) h-=12;
  hh = h<10?('0'+h):h;
  hhhh = h<10?('0'+hhh):hhh;
  AMPM=(ampm=hhh<12?'am':'pm').toUpperCase();
  mm=(m=date.getMinutes())<10?('0'+m):m;
  ss=(s=date.getSeconds())<10?('0'+s):s;
  return formatString.replace("#hhhh#",hhhh).replace("#hhh#",hhh).replace("#hh#",hh).replace("#h#",h).replace("#mm#",mm).replace("#m#",m).replace("#ss#",ss).replace("#s#",s).replace("#ampm#",ampm).replace("#AMPM#",AMPM);
}

function dec2frac(d) {
  var df = 1;
  var top = 1;
  var bot = 1;
  while (df != d) {
    if (df < d) {
      top += 1;
    } else {
      bot += 1;
      top = parseInt(d * bot);
    }
    df = top / bot;
  }
  return top + '/' + bot;
}